Cereal becomes a readily acceptable foodstuff for human beings only after digestion of the starch by heat. The naturally occurring cereal is a "living material structure" just as, however, this is also true of untreated flour and semolina. They are subject to changes through their internal metabolism, becoming depleted in particular in certain components. This process is intensified by the action of heat and light, contact with atmospheric oxygen, moisture, and also through multiplication of degradative microorganisms and other pests. Preservation of foodstuffs having a starch component implies both that tee changes proceeding within them, due primarily to their natural enzymes, are stopped, and also that hhe micro-organisms are killed or their development is impeded. Various processes are available for preservation. These processes should be capable of implementation in a manner wiich is as technically simple and economic as possible. In particular, these processes are also subject to the requirement that the accustomed taste values of the foodstuffs which result are retained as far as possible, and no reduction of the nutritional value or unbeneficial change in the proteins occurs.
In addition to bread, farinaceous products, in particular long farinaceous products and short products, are today particularly widespread basic foodstuffs which are also used to a fairly large extent as reserves.
In general, by farinaceous products are meant ready-to-cook products with good storage capability made from starch-rich, protein-containing ground grain products which are manufactured by shaping and careful drying without the dough mixture being subjected to a fermentation or baking process. Depending on the nature of the raw materials, optionally containing additions of egg, common salt, milk, casein, dry gluten, seasoning or coloring materials etc., a distinction is made between, for example, pasta all'novo (egg-containing) products and egg-free farinaceous products and also semolina and flour farinaceous products.
Excluded from the types of product to be improved by the invention described below are all other grain foodstuffs such as spaetzle, snack-like and bread-like products which pass through the dough stage in their manufacture, but are not usually described as farinaceous products.
The present market offer in relaiion to true farinaceous products essentially comprises by three basic types of farinaceous products, namely the traditionally dried short or long products, the instant farinaceous products in dried form (ready meals, fast food) and also the preserved farinaceous products (undried). Both in the case of the instant farinaceous products and in the case of the preserved farinaceous products the market share is relatively small because of the perceptibly higher manufacturing and selling price and of the quality which as a rule cannot be achieved in comparison with the traditional farinaceous products. In addition to this, in the case of instant farinaceous products, which only have to have hot or warm water poured over them, there is no actual cooking time and cooking temperature of 100.degree. C., which involves a source of risk.
In the case of the so-called classical farinaceous products final shaping is characteristically by means of a mold. In the case of the short products the farinaceous products are cut to the desired length immediately after their emergence from the mold. Examples of this are the short-cut macaroni and macaroni. However, there are also a number of special shapes, for example whirls and nidi (nests), which immediately after emerging from the mold are given the permanent shape by a suitable guide mechanism. This additional shape is lost again by the farinaceous product on cooking. This means that it is then only a matter of conventional spaghetti or noodles. Spaghetti and cannelloni are usually cut to the final length only after drying. The classical farinaceous product is characterized in that it is cooked at the consumer's premises in water for about 10 to 20 minutes on average and has to be processed with additives to form a finished meal. Hereafter this classical farinaceous product is described as "farinaceous product".
The main raw materials of the farinaceous products are durum semolina and durum fine middlings which are expected to have a constant grain-sized distribution, a high protein and yellow pigments content, and also a good pigment stability with little tendency to greyish brown discoloration.
In the dough preparation about 18 to 25% by weight of water are added to the cereal raw materials. The freshly formed farinaceous product contains on average about 30 to 32% moisture, and the finally dried and packed product only about 10 to 14% by weight, in particular about 12.5% by weight.
In the shaping or molding of the starting material for the farinaceous product basically two procedures may be adopted:
(a) the older batch process involving the preparation of a homogeneous, moldable dough in pre-kneading machine and kneading machine (gramola) and molding in hydraulic presses, or
(b) the modern continuous process involving so-called worm presses in which a homogeneous dough is not kneaded in the first section, but only a crumbly dough mass is initially formed in troughs using mixing paddle mechanisms, which mixture is then slowly conveyed by the conveyor worms and fed to the molding head.
The necessary homogeneous kneading or "gluing" of the dough is first effected by the shearing forces in the expressing worm and also the high pressures of about 80 to 120 bar which prevail in the molding chamber and during the passage of the dough through hhe die itself. The homogenized, kneaded, moist and moldable dough is pressed out of the die in the form of a continuous stream of finally shaped dough strands considerably compressed in structure. A fan immediately dries the emerging dough strands superficially in order to remove their stickiness.
Directly below the die rotating knives may be disposed with which the preformed strands are cut to the desired length. It is then necessary to dry the strands so obtained to produce a nonperishable product, drying taking place from the outside inward. In this process it is important that the surface does not harden excessively rapidly before the core in order to prevent splits and cracks in the finished farinaceous product. In general about 1-2% by weight of water is lost through the superficial drying of the farinaceous product after emergence from the molding head.
In practice drying is at present carried out for long products for 8 to 12 hours at a temperature of 70.degree. to 75.degree. C. In known methods for manufacturing the traditional farinaceous products a level has been achieved which it was not possible to raise further in relation to the economic implementation of the process without qualitative losses in the product quality. In more recent times, in particular, reservations have been voiced, not least in consumer circles, in various respects such as gummi dente (well done), instead of al dente farinaceous products, and also questions on the nutritional value and on the undesirable enzymatic reactions etc.
In the Swiss Pat. No. 383,747 a process is described for treating farinaceous products in which the farinaceous products are heated in a zone to 40.degree. to 100.degree. C. or 60.degree. to 80.degree. C. and are then treated with superheated steam at preferably 101.degree. to 170.degree. C. for 5 to 30 seconds. This is followed by drying to produce the final product. This known process is said to eliminate various disadvantages of other processes which were encountered earlier, in particular undesirable enzymatic reactions are said to be prevented. No artificial coloring substances are said to be necessary and shorter drying times are said to be achievable. The farinaceous product acquires a smooth shiny and transparent appearance throug the treatment with superheated steam. Experiments with the recommended values confirm that the results quoted can in fact be achieved and that the use of superheated steam has a beneficial effect on the qualitative features, with the exception, however, of the desirable appearance of the farinaceous product. If a good farinaceous product as desired by the consumer is broken, a smooth, shiny and inwardly transparent structure is perceived at the break. The other surfaces appear matt. Cheap products, the so-called pasta secco (or water-based) products, have a predominantly whitish and matt surface. Pasta all'novo (egg-containing) products have a slightly yellowish to golden yellow tint, but also the glassiness at the breaking point described above. The consumer rates a matt, egg-colored appearance of the farinaceous product as good.
In contrast to this, the product treated with superheated steam acquires an unnatural, almost plastic-like appearance. A consumer views such a product with deep mistrust and regularly refuses to buy it, which does not depend on whether said product has possibly been improved in relation to the substances it contains (lysin and the like).